Segregational stability in R. sphaeroides of plasmids pMG162, pBBR1MCS2, pDK519, and pRK415. The stabilities of plasmid pMG162 (○) and the broad-host-range plasmids pBBR1MCS2 (□), pDK519 (•), and pRK415 (▪) in R. sphaeroides (A) and in R. palustris (B) under nonselective conditions were determined. Plasmid pMG103 (▴) was used as a stable plasmid control in R. palustris (25).